Structural information from methyl internal rotation spectroscopy
Article Abstract:
Structural information related to methyl torsional structure has been derived by use of methyl internal rotation spectroscopy. Barriers to internal rotation and interaction of the methyl with the pi system through hyperconjugation are being investigated. The methyl torsional barrier is affected by changes related to the substituent, its conformation and the its place in hydrogen bonding interaction in para-prime-substituted p-methyl-t-stilbenes in which the changes are 10 atoms from the substitution site. Barriers in the S1 state are very dependent on substituent-related factors.
Publication Name: Annual Review of Physical Chemistry
Subject: Chemistry
ISSN: 0066-426X
Year: 1997
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"Strong" hydrogen bonds in chemistry and biology
Article Abstract:
"Strong" or "low-barrier" bonds are a special class among hydrogen bonds and have strength that may be less than or equal to 10 kcal/mol. They are short and have such a low barrier to hydrogen transfer that it is almost nonexistent. The bonds have distinctive features in the nuclear magnetic resonance (NMR) spectrum, as well. Evidence for the existence of these bonds in small molecules and biomolecules is not conclusive, but they may be significant in enzymatic reactions.
Publication Name: Annual Review of Physical Chemistry
Subject: Chemistry
ISSN: 0066-426X
Year: 1997
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